Underground mining vehicles such as scoops, haulers, equipment movers, etc., powered by electric batteries are well known in the art. In the present battery technology, a fully charged battery normally provides electrical energy for the operation of an underground mining vehicle during one working shift of eight hours. The time necessary for charging a battery is about eight hours. A cooling period of eight hours after the charging is usually recommended for improving the battery performance. Thus, the battery of a vehicle working more than one shift in a 24 hour period has to be charged after every shift. However, for continuous operation of a battery-powered vehicle after the battery has been discharged requires replacement by a charged battery.
During operation of the vehicle, the battery is secured to the structure of the vehicle which supports the battery. However, the vehicle has a battery changing system, usually using hydraulic power, for moving the battery up and down during a battery changing operation. The combination of the vertical motion of the battery provided by the battery changing system and the horizontal motion of the vehicle itself, enables the operator to unload the discharged battery from the vehicle and to load a fresh battery onto the vehicle.
There are different types of battery changing systems, in relation with the battery support, which are well known in the art. In one type of battery changing system the battery is loaded on and secured to a battery support, such as a fork, or a platform, or a "U" shaped structure, etc., which battery support, under the action of vertical hydraulic cylinders, moves up and down during a battery changing operation. The battery support is guided to move in the vertical direction by two parallel members attached firmly to the main frame of the vehicle. The type of battery changing system is similar to the well known load-lifting system of a fork-lift truck. The major disadvantages of this type battery changing systems are: first, the vertical travel of the battery is very short, because the lengths of the vertical hydraulic cylinders and parallel guides are limited by the height of the vehicle main frame, which in most cases is very short; and second, the parallel guides of the battery support are complicated and unreliable because it is difficult to keep them clean in an underground mine environment.
U.S. Pat. No. 5,163,537 and U.S. Pat. No. 5,226,777 both to Radev, disclose a battery changing system for electric battery-powered vehicles having a mainframe. The systems each include a bellcrank for connecting a battery support with the mainframe, an eyebar link for connecting the battery support to the mainframe in parallel with the bellcrank, and a hydraulic cylinder for pivoting the bellcrank. The battery support includes a fork for lifting the battery.
U.S. Pat. No. 5,275,525 to Grumblatt and U.S. Pat. No. 5,664,932 to Clonch et al. disclose battery changing systems which include parallel arms pivotally mounted to the vehicle frame and adapted to be aligned along the sides of the battery. The arms include supports with upward facing surfaces for engaging and lifting the battery.
The prior art battery changing systems require the lifting arms to be aligned with the battery, which in turn requires the vehicle to be maneuvered and aligned with the battery. The prior art systems have been found to be difficult and slow to align. Further, misalignment has caused component breakage. In addition, the prior art batteries occasionally bounce on the lifting arms during transport. Such movement of the battery is unsafe and can also lead to system failure.
The foregoing illustrates limitations known to exist in present battery changing systems. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.